Impellers are fundamental to the operation of centrifugal pumps, turbines, and other fan-based applications. Impellers are typically used as a means of transmitting motion. In aerospace applications, for example, impellers can provide avionics cooling, cabin recirculation, and oil cooling, etc. When developing or manufacturing a new fan/impeller, fine-tuning of design is often needed, to meet a given airflow requirement. This process can be very time-consuming. Consequently, impellers often require longer lead times than other components during the manufacturing process.
Impellers for aerospace applications are typically formed of a single piece of cast metal. Additionally or alternatively, impellers can also be machine-cut from a billet. Often, when developing a new fan or impeller, multiple design iterations are used to test and verify that the fan/impeller meets a given airflow requirement. The design iterations typically include iterations of the impeller's blade setting angle (i.e., its pitch angle). As such, for a single-piece impeller, design iterations require re-making the entire impeller, and the manufacturing processes required to produce these conventional components can be costly and time intensive.
By way of example, the conventional manufacture of cast metal impellers is heavily dependent upon the manufacturing foundry's internal schedule. More than 20 weeks of lead time is not uncommon. In fact, one iteration of a single design can require more than 40 weeks altogether.